Tag Cloud Does Not Display in Ascending Alphanumeric Order

I have a kind of tag cloud box that displays all linked tags from the current set of posts.

I can’t figure out how to sort the tags in ascending alphanumeric order. The tags are all jumbled together without any apparent organization.

Can anyone help? Here’s the code:

<ol id="tagsSubNav"><li>Sort by Type:</li><?php
		query_posts('category_name=retail&showposts=-1&orderby=title&order=asc');
		if (have_posts()) : while (have_posts()) : the_post();
		   $posttags = get_the_tags();
			if ($posttags) {
				foreach($posttags as $tag) {
					$all_tags_arr[] = $tag -> name; //USING JUST $tag MAKING $all_tags_arr A MULTI-DIMENSIONAL ARRAY, WHICH DOES WORK WITH array_unique
				}
			}
		endwhile; endif; 

		$tags_arr = array_unique($all_tags_arr); //REMOVES DUPLICATES
		//echo '<pre>'.print_r($tags_arr, true).'</pre>';

		  foreach ($tags_arr as $tag) {
			 echo '<li><a href="/tag/'.$tag.'">'.$tag.'</a></li>';
		  }

		?></ol>