Shouldn't it be "ir iâ", like the attested "ir Ithil"?

We have i eneth, i arnad, and i innas in Ae Adar Nín so I would say that's equally well attested.

Well, it seems to, strange as it may sound,  to happen often enough to get a saying...

+Hjalmar Holm exactly. I'm sure Gandalf and Glorfindel exchanged some fine anecdotes about Balrogs at the Prancing Pony.

That, and there's the attested phrase 'sui Glorfindel ah i valrog', so there's a precedent for Balrogs :)

Ack, do you remember where that phrase is from, Jenna? My gut is saying one of the later HoME volumes and not VT/PE, but I'm not entirely sure. I'm still working my way through reacquainting myself with the material.

Histories of Middle Earth, though off hand I have no idea which part... I will have a look/think!

Hmm, is it this (from BoLT2)?
"Still do the Eldar say when they see good fighting at great odds of power against a fury of evil: “Alas! ‘Tis Glorfindel and the Balrog”, and their hearts are still sore for that fair one of the Noldoli."

That's all I can come up with - is the Sindarin phrase attested, or a translation?

It's the English that's attested, and that sounds almost right, but the Sindarin was a word for word translation I thought

+Jenna Carpenter I honestly didn't have that in mind when I came up with the saying