Hide based on date

I have a custom coded events post type where the page is working just fine with the exception of not hiding past events. I need the page to auto-hide events as the “start date” is passed

Here is the code for the page:

<?php get_header();?>

<div class="page-container row-fluid">
	<div <?php post_class(); ?> id="post-<?php the_ID(); ?>">

			<div class="breadcrumb">
				<div class="container">
					<a href="<?php echo home_url();?>">Home</a> » <a href="events">Events </a>
					<h1>Events</h1>
				</div>
			</div>

		  <div class="container">
			  	<div class="span8">

			  		<?php 

			  		$args= array(
			  			'post_type'		=> 'events',
						'posts_per_page'	=> -1,
						'meta_key'		=> 'start_date',
						'orderby'		=> 'meta_value_num',
						'order'			=> 'ASC'
			  		);

			  		$wp_query = new WP_Query($args);

			  		//if ( have_posts() ) : ?>

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

			  		<div class="entry-content">
			  			<div class="event-title">
			  				<h2><a href="<?php the_permalink()?>"><?php the_title()?></a></h2>
			  			</div>

			  			<div class="meta">
	  						<p><?php if(get_field('start_date')):?>

	  						<?php $date = get_field('start_date');
	  						// $date = 19881123 (23/11/1988)

	  						// extract Y,M,D
							$y = substr($date, 0, 4);
							$m = substr($date, 4, 2);
							$d = substr($date, 6, 2);

	  						// create UNIX
							$time = strtotime("{$d}-{$m}-{$y}");

	  						?>

	  						<strong>Date:</strong> <?php echo date('m/d/Y', $time);// format date (11/23/1988)?> <?php endif; ?><?php if(get_field('locations')):?>| <strong>Location:</strong> <?php the_field('locations')?> <?php endif; ?></p>
	  					</div>

	  					<div class="clearfix"></div>

			    		<?php the_excerpt();?>
			    		<hr>
			    	</div>
			  		<?php endwhile; //wp_reset_query(); ?>

			  		<?php
					// pagination
					defaulttheme_content_nav( 'nav-below' ); ?>

					<?//php else : ?>
						<?//php get_template_part('not', 'found')?>
					<?//php endif; // end have_posts() check ?>

			  	</div>

		  		<div class="sidebar span4">
		  			<?php if ( is_active_sidebar( 'buttons_sidebar' ) ) : ?>
				        	<?php dynamic_sidebar( 'buttons_sidebar' );  ?>
				        <?php endif;?>
		  			<?php if ( is_active_sidebar( 'events_sidebar' ) ) : ?>
				        	<?php dynamic_sidebar( 'events_sidebar' );  ?>
				        <?php endif;?>
		        	<?php if ( is_active_sidebar( 'general_sidebar' ) ) : ?>
		        		<?php dynamic_sidebar( 'general_sidebar' );  ?>
		        	<?php endif;?>
				 </div>

		  </div>

	  </div>
</div>
<?php get_footer();?>

Can anyone help me figure out what I am doing wrong as I thought the page was already coded to hide an event when the start date passed.

Thanks,