In addition to Roy's spot-on suggestion:
If the problem is in fact caused by using two (or more) hard returns to separate paragraphs -- the "traditional" method from the pre-computer (typewriter) days -- then you could (1) remove all extra hard returns (i.e., leaving just one hard return between paragraphs); then (2) set the paragraph spacing to "2" (or 1.5 or whatever) in Format, Paragraph, Format, "Spacing between paragraphs" at the top of the document.
(Notes: 1. Specific sections of the document can be returned to 1-line spacing with the same setting by selecting the section first. 2. A macro might help to automate the first task of removing extra hard returns. (Ask if you want one.)
This should let WordPerfect set the top-of-page lines to their correct locations whenever you add or delete prior material.
After doing this, you can set Widow/Orphan "on" in Format, Keep Text Together, then check (tick) the box. This is a document-specific setting.
Also: You can "glue" paragraph style headings to their following paragraphs in one operation with a macro on my site: http://wptoolbox.com/library/BPStyles.html. (The macro also adds the Window/Orphan function to the document.)
Obviously, make a backup of the document before doing such global editing.