Sindarin isn't my forte, but "Elros" is translated variously as "Elf of the Spray" or "Star-foam" (Encyclopedia of Arda). To me, it looks like the -ros suffix is "foam" or "spray" (probably the same word), rather than "whisper".

Looking at the Quenya words (which is more my field), "spray" is rosse, while "whisper" is "lussa" or "lusse". I can see that becoming "rus" in Sindarin, but I'm not certain whether any vowel shifts occured...

hS, who still doesn't know Sindarin

Alas! I'm stuck as I don't have a copy of any of the books! And I can't use Haldir or Rumil because they have special heroic rules!

Give me some idea of what kind of name you want and I can go looking for root words that might work for you.

~Neshomeh