Using Lemon Juice against fleas? Does it work?

So, I currently have my lovely 3 year old Aussie on Frontline Combo (plus) and it’s worked splendidly in the past. She’s lived in my flat with no problem with them for quite awhile, however, since then my boyfriend has gotten his own home, and we’ve been spending some more time there rather than my flat. And it seems she’s been itching more. So this evening I got out the flea comb and found a good amount of fleas. I only placed her Frontline on six days ago. Well, I assume since the previous owners had a few dogs that perhaps there were some dormant fleas in the home when he arrived. So, we were looking online and saw that many people use lemon juice on their dogs and in their home to prevent and kill fleas and their eggs. Does it work is my question? I need a quick solution. Thank you.
We already gave her a flea bath