If you are in a large, densely forested area you should be fine (I say "should", because there is no 100% safe area). When you are in a clearing with a few trees, those trees can act like a lighting rod, as you can when you are in open meadow, with you being the tallest thing around.Yes, always known lowest point. I was only more, not less, confused when NOLS article said avoid being under trees, but also an open field. Neither seems reasonable.
In a lighting storm, where the storms is directly above you or near you location, leaving your tent is your safest bet, your tent poles, and any other metal object inside your tent make it unsafe (tent pegs & tripod). If you know ahead of time that thunderstorms are forecasted in that area, seek out a safe zone near you ahead of time, so if it does materialize, you can run straight to it, instead of running around looking for one in the rain/hail.And leaving a tent? I want to know - would anyone do that in middle of a storm that has lightning ? Is that actually the right thing to do? I would assume taking shelter is the right call, then get on a mat, take off any metal, and pray.