title: Need a regular expression to match letter followed by number or capital
body: <p>I need a regular expression that can replace the lowercase letter <code>n</code> with a newline, but only when it is followed by a digit <code>0-9</code> or a capital letter.</p>
  
  <p>For example, the string:<br>
  <code>Company Buildingn100 Prospect Way</code></p>
  
  <p>Should convert into:<br>
  <code>Company Building<br>
   100 Prospect Way</code></p>
  
  <p>I'm trying to sanitize this data in PHP, so the resulting expression needs to be compatible.</p>