Sort list of WordPress Page under tag when is_tag() called

You could merge order parameters into the query when it’s a tag page..

Replace the following lines.

<?php /* If this is a tag archive */ if( is_tag() ) { ?>
  <h2>Lawyers in <i><?php single_tag_title(); ?></i> Practice Area:</h2>
<?php } ?>

with..

<?php 
if( is_tag() ) { 
    $args = array_merge( 
        array( 'order' => 'asc', 'orderby' => 'title' ), 
        $wp_query->query
    );
    query_posts( $args ); ?>
    <h2>Lawyers in <em><?php single_tag_title(); ?></em> Practice Area:</h2>
<?php } ?>