Forcing HTTPS with Wordpress on AWS

Question

It works on our home page. so if you go to www.domain.com or http:// www.domain.com it will force you to https://. So that works.
But if you go directly to http:// www.domain.com/about-us it won't force you back to https. If you go to https:// www.domain.com/about-us it works fine. But You have to manually put the 's' in.

I'm running the 'Wordpress HTTPS (SSL)' plugin.

In my htaccess I have:

RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule ^.*$ https://%{SERVER_NAME}%{REQUEST_URI}

And in my wp-config I have:

define('WP_HOME','https://www.domain.com');
define('WP_SITEURL','https://www.domain.com');

define('FORCE_SSL_ADMIN', true);

if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false)
       $_SERVER['HTTPS']='on';

EDIT WITH SOLUTION

I'm not going to mark this as solved since I don't know why this solution worked for me, as the code should actually work the way I have it based on everything I've read from here and from Amazon concerning their ELBs. The important thing to remember that the X-Forwarded-Proto is the key here and is the header passed through the ELB. https://aws.amazon.com/premiumsupport/knowledge-center/redirect-http-https-elb/

I ended up moving the RewriteCond & RewriteRule from the .htaccess to my .conf file and everything is working now as expected.