You all made my point for me. My so-called "friend" was attempting to sell me a flat statement that elevator controls speed-period, and throttle controls altitude-period. From what I can see here, and from 30+ years of my own observations while flying R/C, it all depends on the airplane in question, and what flight regime the aircraft is in at the time.
We all know a plane can and WILL climb with just application of elevator, provided it has sufficient speed to maintain flight both before and afterwards. The tradeoff is airspeed, eventually losing speed until it's nose drops (but it DID climb!). So it can be said that elevator controls (or affects) altitude AND speed.
I have seen and flown airplanes that flew so neutrally that increasing throttle would change only speed, but not cause a climb. So the same thing applies. It depends on the aircraft, it's trim, and other factors affecting the plane.
My point to him was that it couldn't be said as a "general statement". He didn't get it.

Don't ask me what he said about rudders on an airplane...LOL

Rick