ucwords with abbreviation exceptions
<p>How do you turn this text:</p>

<blockquote>
  <p>NEW LOW FOR US-PAKISTAN RELATIONS</p>
</blockquote>

<p>into this text:</p>

<blockquote>
  <p>New Low For US-Pakistan Relations</p>
</blockquote>

<p>PHP's <a href="http://www.php.net/manual/en/function.ucwords.php" rel="nofollow">strtolower(ucwords($string))</a> would turn "US-PAKISTAN" into "Us-pakistan". However, I'd require the acronym "US" and the "P" from Pakistan to stay uppercase. How can I best achieve that?</p>
