One of the keys to using the Eldarin languages is feel, and 'Glordil' feels horrible. It feels like an orc's name ('Glordil laughed his horrible laugh. 'No, elf,' he snarled, 'there will be no escape for you').
I'm assuming, based on your description, that Laurëandil is the original form of the name. When the Noldor came over, they didn't really know Sindarin - as a result, a lot of their 'translated' names are just 'soundalikes'. By that method, you could have a name like Lothendil/Lossendil.
But let's say she and her husband bother to learn a little of the local language before translating her nickname. You're right to use the 'Glor-' words for 'gold' - they have the same root as 'laurë'. The Ardalambion Sindarin wordlist gives these entries:
GOLD (as metal) 1) malad (i valad), pl. melaid (i melaid) if there is a pl. 2) malt (i valt), pl. melt (i melt) if there is a pl. (VT42:27). ”Gold” in extended senses: glawar (i ’lawar) (sunlight, radiance of the Golden Tree Laurelin), pl. glewair (in glewair) (VT41:10) GOLD (COLOUR?) *mall (i vall), pl. mail (i mail) if there is a pl. – Suggested Sindarin form of ”Noldorin” malt.
GOLDEN 1) (of gold) malthen (melthin- in compounds; lenited valthen; pl. melthin), 2) (shining with golden light) glóren (glórin-), lenited ’lóren; pl. glórin, 3) mallen (lenited vallen; pl. mellin).
GOLDEN LIGHT glaur (i ’laur), pl. gloer (in gloer)
I can see three useful words there: glawar (sunlight, or the light of Laurelin - use if she was named after the Tree), glóren (glowing like gold), and your choice of glaur (golden light), which clearly turns into Glor if you happen to be, say, Glorfindel.
As you noted, -(n)dil (and the related -(n)dur) show up in Sindarin names all the time - Elendil springs to mind - and that seems to be a Noldorin habit. So you can certainly use that.
That gives three names: Glawardil, Glorendil, and Glaurdil/Glordil. As I say, the last should be avoided entirely. Glorendil works fine, and sounds a lot like her Quenya version. Glawardil - or, potentially, Glardil - would also work, but doesn't sound quite as nice, at least to me.
If you wanted to go full-on translation...
FRIEND 1) (masc.) mellon (i vellon) (lover), pl. mellyn (i mellyn), coll. pl. mellonnath. Also meldir (i veldir), no distinct pl. form except with article (i meldir). Also seron (i heron, o seron), pl. seryn (i seryn), coll. pl. seronnath. 2) (fem.) meldis (i veldis), no distinct pl. form except with article (i meldis), coll. pl. meldissath.
FRIENDLY milui (lenited vilui; no distinct pl. form) (loving, kind)
FRIENDSHIP gwend (i ’wend, construct gwen) (bond), pl. gwind (in gwind), coll. pl. gwennath. Note: a homophone means ”maiden”.
That gives meldis (female friend), milui (loving, as an adjective), and gwen (friendship). Glorwen is a possible - it uses the common -wen (maiden) ending as its homophone. Gloremilui has an interesting sound, though terminal vowels aren't very common in Sindarin. Gloremeldis (Golden Friend) is probably your best literal translation with the 'friend' interpretation.
And one final entry:
LOVE (noun) meleth (i veleth), pl. melith (i melith)
LOVE (vb.) mela- (i vela, i melar), pa.t. melant (VT45:34)
LOVE mîl (i vîl) (affection, kindness), no distinct form in pl. except with article (i mîl), coll. pl. míliath
LOVER 1) (fem.) melethril (i velethril), no distinct pl. form except with article (i melethril), coll. pl. melethrillath. 2) (masc.) melethron (i velethron), pl. melethryn (i melethryn), coll. pl. melethronnath. Also (when lover = ”friend”) mellon (i vellon), pl. mellyn (i mellyn). Coll. pl. mellonnath.
LOVING milui (lenited vilui; no distinct pl. form) (friendly, kind)
We've already seen 'milui', of course, so other than that we have 'melethril' (lover), 'meleth' (love, as a noun; I think that's 'my love'), 'mîl' (noun again, = affection). Melethril is way too long (Gloremelethril), but could be contracted as 'Gloremethril' if you liked the sound. 'Gloremil' is a possible, but I think it's too heavy on the 'o' sound. 'Glormeleth' is also an option.
My final list of possible names, then, in no particular order:
Glawardil
Glorendil
Glorwen
Gloremilui
Gloremeldis
Gloremethril
Gloremil
Glormeleth
Oh, and I've just noticed:
Glaurwen
Glaurmeleth
Glawarwen
In fact, you could probably heavily contract 'glawar' down to 'gla', and replace 'glore' with it in most of the above. That gives things like:
Glamilui
Glameldis
Glamethril
Those sound rather Welsh to my ear, actually, like relations of Gwalchmai.
Anyway: any of those names are valid in Sindarin. 'Glorendil' is probably the most natural for your characters to come up with, but if you prefer the sound of one of the others - that's how Elves work!
Also: really? Only one year? Strewth.
hS