Here's the deal —cardio is not a warm-up. The goal of proper warm-up is to increase body temperature (which cardio does), prepare central nervous system for an upcoming activity, increase mobility to be able to train through full range of motion.

Cardio achieves only one of those. And if you're going to do the upper body workout, cardio as a warm-up tool is almost useless because it does nothing to prepare your body for workout-specific work.