Is it possible that you are subscribing to your Lotus Notes calendar directly from the Google site, and only getting them 'second hand' that way? Because I don't know of anyway to directly sync Calendar to a Lotus Notes server (though I could easily be wrong about that).
If that is the case you're problem may lie between Google and the Lotus calendar, not in the Calendar app on the iPad.
If it does not reveal any personal data, could you post a screen shot of your calendar with the Calendars displayed, like I did? You can use Skitch (a free app) to cover any personal info and crop (also, like I did). I want to see exactly where the My Calendar is showing up.
Screen shots can be taken by briefly pressing the Home and Power button at the same time.