Immortality and the sons of Elrond

[TheGreatElvenWarrior]

Originally Posted by PrinceOfTheHalflings

"The Tale of Aragorn and Arwen" mentions that when Arwen visits Lorien after Aragorn's death it is deserted. The Elves have left. Presumably Elladan and Elrohir had also left Middle Earth by that time, because otherwise Arwen might have chosen to spend her last days with them.

What if they had died by that time? Could they have decided to have a life of a human too? Because doesn't it say in the Silmarillion that if you were of Elrond's lineage you could choose whether or not you wanted to be an elf or a human. I vaguely remember reading something about that about two weeks ago.