I’ve had a look at the page source and this is the code that my plugin is adding to the page…
<!-- YouTube Embed v3.3.2 -->
<div itemprop="video" itemscope itemtype="https://schema.org/VideoObject">
<meta itemprop="thumbnailUrl" content="https://i.ytimg.com/vi/LrwHEgfRgNU/hqdefault.jpg" />
<meta itemprop="embedURL" content="https://www.youtube.com/v/LrwHEgfRgNU" />
<meta itemprop="height" content="340" />
<meta itemprop="width" content="560" />
<iframe frameborder="0" style="border: 0;" class="youtube-player" width="560" height="340" src="https://www.youtube.com/embed/LrwHEgfRgNU?enablejsapi=1&modestbranding=1&fs=0&rel=0&wmode=window" ></iframe>
</div>
<!-- End of YouTube Embed code -->
This is 100% correct and if you past the src URL into your browser you’ll see the video appear. So, basically my plugin is doing what it should. I can only assume that something else is interfering. The CSS for your site looks fine but it may be another component of your theme or a plugin (not that you appears to have that many installed).
As much as it pains me to suggest it (because I hate it when people suggest this to me) you should probably try switching off your plugins one-at-a-time to see if any of those are the cause.
You could also try putting the YouTube URL directly on the page on its own line – WordPress will automatically convert this to a video – try that to see if the video appears then.
David.