Dear G; Tried to find you...

[Eruanna]

One of the medieval herald's tasks, apart from announcing challenges and later recounting a chronicle of the battle, was to 'keep an eye on' his leader's warriors so that he could report on their progress, state of health etc during the battle. He had to take messages up and down the battle lines. He would, of necessity, have been armed, as he was in great danger (an easy target, waving his lord's banner about)
I tend to agree with Garen and Mithalwen, there is no definite proof that Elrond did not fight in battle.
In 'The Hobbit', Elrond is described thus:

"...as noble and as fair in face as an elf-lord, as strong as a warrior, as wise as a wizard, as venerable as a king of dwarves, and as kind as summer."

In describing him in warrior-like terms then surely Tolkien did not exclude the possibility that he might have been a warrior.