<!DOCTYPE html>
<style>
div {
  width: 10ch;
  border: solid;
}
</style>
<p>H should be followed by a hyphen, and x should not.</p>
<div>xxxxxxxxxxxxxxxH&shy;xxxx</div>
<div>xxxxxH&shy;xxxxxxxxxxxxxxxH&shy;xxxx</div>
<div>xxxxxH&shy;xxxxxH&shy;xxxxxxx</div>
<div>xxxxxH&shy;xxxxxxxxxxxxxxxx</div>
<div>xxxxxH&shy;xxxxxxxxxxxxxxxx xxxxxxx</div>