Renaming the Home Page

I’m using a child theme of Twenty Twelve and my website url is: https://docscapes.org .

The home page of this site lists upcoming screenings in this film series. I would like the home page to show the title: Upcoming Screenings.

Right now I am using display-none in the CSS to not show the page title because it looks like it will only display the title of the first post on the page.

I tried inserting a home page title in the child theme’s index.php, above the loop, but that doesn’t appear.

I tried copying this function from the Twenty Twelve functions.php into the child theme’s functions.php file and changing true to Upcoming Screenings, like so:

function twentytwelve_page_menu_args( $args ) {
	if ( ! isset( $args['show_home'] ) )
		$args['show_home'] = "Upcoming Screenings";
	return $args;
}
add_filter( 'wp_page_menu_args', 'twentytwelve_page_menu_args' );

But when I upload the revised child theme functions.php, the site goes down, I get only a white screen.

Thanks for any suggestions.