Hemp said it . Don't cut anything, it may look like the lower parts are not getting light but that's only half the story. The leaves make energy for the whole plant, That's the lower half too. Just because the light doen't shine on them doesn't mean they are not getting energy from the ones that are getting light. If they turn half or more yellow then that leaf is used up and take it off. Leaves are the muscle of the plant, as long as they are green they are good. Some of my best buds grow in the shade.