How to add span element around specific words

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jQuery(document).ready(function(){
jQuery('.page-id-24048 .site-content #page-header .page-heading h1.entry-title').each(function() {
  var textArry = jQuery(this).text().split(" ");
  jQuery.each(textArry, function(index) {
    if (textArry[index].match("^M") || textArry[index].match("^L"))
      textArry[index] = '<span class="mention">' + textArry[index] + '</span>';
  });
  var output = textArry.join(' ');
  jQuery(this).html(output);
});
});