Thanks JSWolf. But when I investigated the Calibre-generated html in the zip folder I found that there was no pagebreak shown between the Title and Author. Hmm. And then I found this section in Calibre under Preferences/Conversion/Page Structure:
Insert page breaks before (Xpath Expression):
//*[name()='h1' or name()='h2']
I thought this section was part of the one above that deals with preprocessing and since I didn't have that checked I thought it wasn't applied by Calibre. Seems I was wrong.
As soon as I removed that jazz above (just completely cut it out) the book titles and authors now appear on the same page.
It's all there, one just has to track it down
So problem solved!