[Mamzelle]

My guess--Elrond's taking over the role of his sons in delivering Arwen's banner, and giving Aragorn the "bad news" that Arwen will leave Middle Earth. Of course WE know she won't, but that will add some drama to Aragorn riding into battle with a broken heart.

[ElfArcher]

I never thought of that!!
And it would explain all the weird Arwen stuff in TTT.

If you're right( I think you are) the "meeting" will probially take place sometime after Aragorn and Eowyn depart. Otherwise Eowyn would see Aragorn sad and...