Does the arranger track work with parts that are not a square 4 or 8 bars?

I have drawn in some events in my project window on the arranger track and realize that many of my parts actually start with some material before the beginning of the bar. for example, the bassline might have a few notes that run into the main groove or a vocal may start with a few words sung before the beginning of the bar. How does this fit in with the arranger track? Would I have to actually start the arranger track event early to incorporate this material or would it be better to create a seperate event for just this bit before the beginning of the bar? I am sure this must work somehow since in music things are not so “square”.