Edit in JSFiddle

// DOM ready
$(function() {
    
    var $h1 = $('h1');
    $h1.html(unOrphan($h1.text()));
    
});

function unOrphan(str) {
  return str.replace(/ ([^ ]*)$/, '&nbsp$1'); 
}

<h1>This heading shouldn't have an orphan, try giving it a resize</h1>