How can I avoid a lightbox from popping up on each webpage in squarespace?

From what i've read, I cannot use the .php code for squarespace. I'd like my form to only populate when they initially visit the website, but not with every page click. 

To my understanding, you have embedded your form to your Squarespace website using lightbox, is that correct? However, every time you switch pages on your website, lightbox always pops-up, is that correct?

I tried to check your website https://mlhofcva.squarespace.com/#welcome-section and have not seen the form embedded in it unfortunately. 

Can you help us understand your concern more by giving us a little more details, please? May I also ask where on your page your form is embedded? And what form is embedded? 

If you can post a screenshot, that would be great. 

We will wait for your response. Thank you.