Make sure a string never has a widow.

dewidow.php

<?php
/**
 *  Make sure a string never has a widow.
 *
 *  @param   string  $text       The string to dewidow
 *  @param   int     $min_words  Minimum number of words to dewidow
 *  @return  string              The dewidowed string
 */
function dewidow( $text = '', $min_words = 3 ) {
    $return = trim( $text );
    $pos = strrpos( $return, ' ' );

    // Check if a space exists
    if ( $pos !== false && substr_count( $return, ' ' ) > ($min_words - 1) ) {
        $return = substr_replace( $return, '&nbsp;', $pos, strlen( ' ' ) );
    }

    return $return;
}