Firefox: Set a specific link to always open in "private browsing" mode

My Firefox 40.0.3 home page is a local html file with links I frequently visit. How can I set a particular link in that file to always open in Private Browsing mode?

For example, I want to know if it's possible to modify
<a href="http://www.somewhere.com/">Somewhere</a>
so that when I click on the "Somewhere" link, it'll automatically open in a private browsing window.

(I know I can right-click on the link and then choose "Open Link in New Private Browsing Window" but I sometimes forget and click it directly.)

I'd prefer a solution that doesn't require an extension.

Edit: I came across a forum post indicating that what I want may not be possible: How to start firefox from command line as private browsing.

So, in case there's no direct way to do what I want, I'll use this script and bind it to a convenient keyboard shortcut:

#! /usr/bin/env bashfirefox -private-window http://www.somewhere.com/