Breaking Bad
It’s bad form to force a page break mid-sentence.
That goes for dialogue and action lines.
Some of the better screenwriting software programs will not even allow you to do this. They’ll automatically force a page break after the completion of an earlier sentence instead of cutting off dialogue or scene description abruptly, then continuing it on the next page.
Why? Because it causes an unnatural break in the reader’s attention and in the images being conjured. The last thing you want to do is jar someone from what had been an enjoyable reading experience.
Check the preferences in your software program to see if you can do this automatically. I know for sure that Final Draft and Move Magic Screenwriter offer this feature (although, I believe Movie Magic Screenwriter may have this feature disabled by default).
BONUS TIP
Never break a page immediately after a scene heading — whether it’s a master scene heading (e.g. EXT. ALIEN SPACECRAFT – NIGHT) or a secondary scene heading (e.g. KITCHEN). If you correctly format these sluglines as scene headings (versus action lines), your screenwriting software should take care of the rest.