The problem with an elevation view is choosing the point of view and having appropriate representations of the objects. A softbox or flat reflector at 45 degrees right of the subject and 35 degrees up would look very different from the camera perspective, from stage left, or from stage right. And then there’s the horizontal angle relative to the subject (“feathering”), which would get confusing with only one representation of a lighting or reflecting fixture. I agree this is a similar problem with vertical angles in a plan view. One would still need notes.
I certainly understand Robert’s concerns. I’m just having a hard time conceiving of how one would draw this without many versions of each lighting fixture drawn from different angles.
How’s this for an idea? Use a set of two graphs, with x,y axes graduated in degrees, 90 degrees left and right, 90 degrees up and down. Base one on the subject’s point of view with the camera at 0,0, and the second graph with 0,0 at the point opposite the camera relative the the subject’s position. Place elements at the correct vertical and horizontal angles relative to the line from subject to camera. You might still need some indication of how to “feather” fixtures relative to the subject, but this would take care of what I think are your basic concerns about lighting source placement angles relative to the subject.