My apologies Andy - it's a failing of mine to sometimes go in too hard when it's not warrented. I did that here. Sorry.
I was thinking last night about how better to get my point across (without being confrontational) and came up with the comparison between night shots of lightning and those from daylight hours. The lightning doesn't get brighter during the day compared to at night, so you need to use the same apertures as those you would choose at night. Thus if you want to get the base exposure correct (ie that for ambient light) you'll need to use a short exposure time.
In any case, do have fun trying out different methods. Lightning photography is anything but boring when you're out there making the images. Good luck with it.