Of tangential relevance: On the aircraft I was trained on, it was SOP to set the igniters = ON when encountering some significant amount of precipitation in fli

Of tangential relevance: On the aircraft I was trained on, it was SOP to set the igniters = ON when encountering some significant amount of precipitation in flight, as a defense against a water induced snuff-out. (I forget exactly how the precip threshold was determined.) Otherwise, as parent said, the flame persists following engine start, and so the "spark plugs" (igniters) are not kept active.