I apologize. I just tested the macro to be sure. I was wrong.
Graham's solution does not work in the current version of Word (2021 / 365) and may not work in Word 2016.

An AutoOpen macro apparently runs before the Pick Up Where You Left Off is implemented. So it does take you to the beginning of the document but then you get bumped to the last editing point.

Ctrl+Home remains a workaround.