Yes, there are written rules, such as those in the Chicago Manual of Style. My 15th edition, 3.11 (page 94) says that:
"A page should not begin with the last line of a paragraph unless it is full measure and should not end with the first line of a new paragraph. Nor should the last word in any paragraph be broken--that is, hyphenated, with the last part of the word beginning a new line. To correct any of these occurrences, page length may be adjusted. (A very short line at the top of a page is known as a "widow"; a single word or part of a word at the end of a paragraph is an "orphan.")
This doesn't specifically address the situation you describe, but the general concept (the heading of 3.11) is *Overall appearance."