Set default Apache Solr results sorted by Title

/**
 * Set default solr results sorted by Title.
 */
function hook_apachesolr_query_prepare(DrupalSolrQueryInterface &$query, &$caller) {
  if (this_is_my_page()) {
    foreach ($query->getAvailableSorts() as $key => $value) {
      if ($key == 'sort_label')
        continue;

      $query->removeAvailableSort($key);
    }

    $query->setSolrsort('sort_label', 'asc');
  }
}