Pagination not working with custom loop

I’ve created a loop that filters the posts depending on a custom taxonomy called “areas”. This is so that I can have two “home pages” on the same site, displaying posts that are relevant to those areas. All well and good; it works great – until I noticed the posts_nav_link wasn’t displaying anything. I’ve read around the subject, and understand that pagination won’t work on a custom loop – without a workaround – unfortuantely, I don’t have the skills to work it around! If anyone would be willing to have a look at my code and advise me – I’d be very grateful!
My code:

<h2 class="section-title">Latest Articles</h2>
<?php $args = array(
'post_type' => 'post',
'tax_query' => array(
array(
								'taxonomy' => 'areas',
								'field'    => 'slug',
								'terms'    => 'abergavenny',
								'operator' => 'NOT IN',
							),

						),
					);
$query = new WP_Query( $args ); ?>

<?php if ( $query->have_posts() ) : while ( $query->have_posts() ) : $query->the_post(); ?>

<div class="item">
<h2><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>

<p class="date-stamp">Posted on: <?php the_time( 'F jS, Y' ); ?></p>
<div class="entry">
<?php the_post_thumbnail('thumbnail'); ?>
<?php the_excerpt(); ?>
</div>
<div class="clear"></div>
<p class="postmetadata"><?php _e( 'Posted in' ); ?> <em><?php the_category( ', ' ); ?></em></p>
</div> 

<?php endwhile;
wp_reset_postdata();
else : ?>
<p><?php _e( 'Sorry, no posts matched your criteria.' ); ?></p>
<?php endif; ?>
<div class="navigation">
<?php posts_nav_link();?><br>
</div>