Novorapid is at its most active peak between 1 and 2 hours see graph
http://www.diabetes-support.org.uk/info/?page_id=408
I've been using the stuff since 1998 though and nobody could expect you to know stuff like this after the first 5 minutes so I wouldn't think about it too much - and certainly until you know whether your basal keeps you steady in the background - you can't possibly nail it all down properly anyway. What you are looking for at the moment is, does the Novorapid bring me down to what it was just after 4 hours ago, and that's that.
Not sure what sort of place you work, but - can you not vary your lunch hour - even just occasionally for something special - like going without eating lunch for an extra hour or eat something not messy, at your desk? Or do without breakfast entirely and do the morning basal test at work?