I would like to present a BreezingForms form in a popup using LightBox. Can I do that?

Yes, you can.

Add the code below into the index.php of your template -- let's say as the very first line:

<?php JHTML::_( 'behavior.modal' ); ?>

For index.php files that consist of PHP only, (e.g. YooTheme templates), then use this

JHTML::_( 'behavior.modal' );

Then you can add a link to any of your pages like this:

<a href="http://yourdomain.com/index.php?option=com_breezingforms&ff_name=FORMNAME&tmpl=component" title="My Form" class="modal" rel="{handler: 'iframe', size: {x:570,y: 200}}">My Form</a>

Replace yourdomain.com with your domain (and also use https if you are using it instead of http), then FORMNAME with the name of your form and use the x and y values to define the size for the modal window.

(If it does not work using that code, try changing index.php to index2.php.)