I don't think it's clear what you mean. What kind of page break? What
kind of block of text?
As far as i know there is only one page break. Block of text is a "TextStyleRange" or a "Paragraph"
This will return a regular single character "\r" for a hard return at the end, but any of ID's breaks will be indicated by one of the values:
(as you can see there is more than one 'break' character).
To check a page break before the current paragraph, you will have get a pointer the paragraph before the current one and do this same check on that.
Check also the constant
which can be
indicating the Keep Options applied to the current paragraph. These also make paragraphs start at a new page.
Finally, there is the possibility that none of the above applies, but the previous paragraph ended right at the bottom of a text frame, and the current paragraph starts at the top of a new frame. No special character or code, but still a page break. (Perhaps you could test paragraph.lines for that.)