Last night saw the most intense electrical storm I remember for years. There must have been at least quarter an hour of activity, rumbling thunder and searing flashes. I was tempted to get my camera out but, since it has been years, I couldn’t remember the ideal settings so I decided to enjoy the show rather than trying to record it.
From subsequent research, slow shutter speeds (perhaps 30s), wide aperture and a tripod. The lightning should act like a flash, freezing short moments with the tripod ensuring the background lines up between images.