hide-editor.php

<?php

/**
 * Hide editor on specific pages.
 *
 */

function hide_editor() {
	global $pagenow;
	if( !( 'post.php' == $pagenow ) ) return;
	
	global $post;
	// Get the Post ID.
	$post_id = $_GET['post'] ? $_GET['post'] : $_POST['post_ID'] ;
	if( !isset( $post_id ) ) return;
	
	// Hide the editor on the page titled 'Homepage'
	$homepgname = get_the_title($post_id);
	if($homepgname == 'Homepage'){ 
		remove_post_type_support('page', 'editor');
	}
	
	// Hide the editor on a page with a specific page template
	// Get the name of the Page Template file.
	$template_file = get_post_meta($post_id, '_wp_page_template', true);
	if($template_file == 'my-page-template.php'){ // the filename of the page template
		remove_post_type_support('page', 'editor');
	}
}
add_action( 'admin_head', 'hide_editor' );

This is nearly identical to the original but I added the change suggested in the comments.