Elfhelm

While Elfhelm is ready, he gains: " Response: After your threat is raised as the result of questing unsuccessfully, or by an encounter, or quest card effect, reduce your threat by 1.""

Song of Earendil

Attach to a * Hero

Response: After song of Earendil enters play, draw 1 card.

Response: After another player raises his threat, raise your threat by 1 to reduce that player's threat by 1.

My question is can you use the Song of Earendil to lower your friends threat by one but then follow that up with Elfhelm to cancel the threat raise? Or does it not work because the threat raise was caused by the Song?

Elfhelm does not work in that situation, because the Song of Ereandil is a player card effect not an encounter or quest card effect.

Good question. Though I must concur with Plueschi on this matter