"Oh good," she says, and rushes out into the street and into his arms.

Awww.

They will both start singing!

Pretty. How do they both know the lyrics and the harmony, though, that's the question -

It has never occurred to me to ask how Elves coordinate all the singing and even if it had I suspect my question would stand what with one of those people being a non-Elf.

Osanwë- and yeah, she has to be leading -

So it's improvised on the spot? How very musical-logic.

Musical logic?

Earth art form, did you never run into any? Theatrical or film productions where the characters start singing without any of them acknowledging that this is not a human-typical activity - it's sort of hard to describe the way in which it's conventional for the songs in musicals to work, we normally pick it up by exposure...

Anyway, I expect they're improvising. 

Cute.

Yeah.

A crowd is gathering.

Is the audience part of their cunning plan or incidental?

I'm sure it's deliberate.

And they'll announce their engagement when critical mass has assembled or something?

You've got it. Critical mass or at least some people with cameras.

Giggle. Swaying to the music.

It's very pretty music!

Lovely!

Of course it is.

And when lots of people have assembled they kiss, and giggle, and she whispers something even Elf hearing can't, and then they both say simultaneously "will you marry me?" 

I will have to find them a nice present.

You already did, you know. She squeezes her hand. It's safe enough; no one is looking at them. 

All right, then I will have to find some very nice wrapping paper and roll you up in it and add a fetching bow.

I am sure Tirion will be offering nothing but wedding presents for the next Year.