I downloaded three of the recommended utilities. One was a dead link.

The first, OnTop, is freeware, so naturally I tried that one first. It
does the job and if it continues to do the job real-time (I'll know on
Tuesday) won't bother with the other two, which are shareware.

OnTop is a simple, small executable with an companion dll. No
installation is necessary. I just put both in my utilities
subdirectory, and when I load OnTop it resides in the system tray. It
works by adding an option to the top  left button of Excel (where
Restore, Minimize, and Close are) that says Stay on Top.