Here's one approach.

... predict when the date will need to be changed in the
A column to the next date.

Presumably,
- you already have a way to get the start date in A10, and
- the time values in column B don't have the date included invisibly.

In A11, put
=IF(B11=B10,"",MAX(A$10:A10)+1)
and copy down.

... making the time schedules in the B column invisible
if there is no value in Q34

Since you are satisfied with your formulas in column B, they can be nested within an IF() to accomplish this:
=IF($Q$34="","", [your_formula])
Presumably, the formula in B11 is already copied down to subsequent rows, so the update can proceed the same way, without editing each individual formula.

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A different approach is to use conditional formatting. That way, the values are still in the cells, but (essentially) written with ink matching the background when needed to make them invisible.