Make no mistake, as you push the hips forward, the bar should dip slightly, which means the elbows should dip slightly as well. However, the elbows start the lift slightly in front of the bar and should stay slightly in front of the bar during this process (Figure 2). In other words, the elbows will dip down, but they should not drift backward as well.
If the elbows drift back (Figure 3), it greatly increases the chance that you will launch the bar forward. To fix this error, cue yourself to “keep the elbows forward” while you reach with your hips. The shorter version of this cue is simply “elbows forward.”