According to this blog article, you should use the display: inline-block
property on a div
selector that encloses your header and paragraph.
Here is an excerpt from the said article:
If you set the display
property for a div
to be inline-block
,
iBooks will display the contents of the entire div
together on a
single page, skipping to a new page if necessary, unless the entire
div
can't fit on a page by itself, in which case it will be divided
across pages.
It's simple and very powerful: div {display: inline-block}
Here's a short document with no inline-block
display. Notice how the
header is separated from the paragraph that follows it, and even how a
bit of the background bleeds through to the following page. Icks. The
image and caption are likewise separated. Terrible!


Here's the exact same document with one div
enclosing the header and
paragraph and second div
enclosing the image and caption. Both
div
s were set to display:inline-block
. The result? Goodbye widows
and orphans:


Where can you use this? As shown here, if you have a series of
illustrations with captions, use inline-block
to keep the caption
right under the illustration.
If you want a header to never appear alone at the bottom of the page,
but always be followed by at least one paragraph, just enclose the
header and the paragraph in an inline-block
div
.
The article that I have linked also contains two epub files that can be used as a reference for these examples.