Yes, you could do this in LotRO (which, btw, wasn't made by Decipher, but rather Worlds Apart). Even so, you can't ALWAYS go by what happened in LotRO, as there are still bugs in that program where cards are played incorrectly.
That being said,
Wulf CAN respond to the Mob's skirmish win with his ability, even if he was just played then. Thranduil got it right.