If a Storm Sorcerer casts Dragon’s Breath and chooses lightning as the damage type, does that initial casting trigger the extra damage from “Heart of the Storm”?

PS. Love Xanathar’s, it’s a perfect addition to 5e!Yes, dragon's breath can trigger Heart of the Storm if you pick lightning. ⚡️

— Jeremy Crawford (@JeremyECrawford) November 10, 2017