There is an option in Kobo eReader.conf (.kobo/kobo) on a Kobo that will ignore widows/orphans with epubs. This can be overridden in the CSS. But if you remove all widows and orphans from CSS or set them to 1, this should work.
Code:
[Reading]
readingAdobeOrphans=1
readingAdobeWidows=1
You can edit the conf file with Notepad.