See if "posts page" is set in Settings > Reading; If it is, display that page's title before the posts.

index.php

<?php  
// See if "posts page" is set in Settings > Reading, aka is_home()
// If it is, display this page's title before the posts
$page_for_posts = get_option( 'page_for_posts' ); 
if ($page_for_posts) { ?>
	<header class="page-header">
		<h1 class="page-title" itemprop="headline">
			<?php echo get_queried_object()->post_title; ?>
		</h1>
	</header> <?php // end article header ?>
<?php } ?>