It works if it's in your inventory. When you wield items you use them as weapons. Hmm, I wonder if lamp/latern works as flaming sword: "You hit zombie with latern. Your latern burns zombie..."
Edit: It didn't but this message was worth trying it: "You strike the young female carnivorous mutant bunny! You advance to skill level 1 with your latern! The young female carnivorous mutant bunny is slain.