I have a WP.com site, so I don't know what version I'm running. I can't see that snippet anywhere.
I have a rather clunky workaround for the way the editor removes blank lines. There are still a few quirks I don't understand, but I have made my page look the way I wanted-ish.
Create yourself an image the same colour as your background, in my case, white. If it's too small, you may have to edit it in the Text Editor.
Insert the image where you want the blank lines.
Fiddle with the height to get as close as your desired height.
Remove the Alt text otherwise it shows briefly when you display the page.
Two quirks I know of -
1. I can't make it small enough to give a single blank line.
2. As you increase the height, it seems to stop pushing what's below it down. Temporary solution, until I find out why, is to add multiple instances of the image.