Is not that simple. A DDoS attack can be made to the IP or the domain and there are a variety of DDoS attacks. If you manage to hide your real IP using CloudFlare you will mostly avoid the Layer 7 attacks because CloudFlare will cache that files so they won't screw you with some images being embed on several websites because CloudFlare won't issue a request to your host. This was the way that I manage to overcome when the demo was DDoSed.
Problem comes with dynamic content because that isn't cached. This means that all the traffic is passed through your host and they label you as a under DDoS domain and they will mostly shutdown until the attack is gone. So, if you use the CloudFlare basic plan you will have to go to the "I'm under attack mode" and wait until the attack is over.
But, even with CloudFlare business you don't have real protection. Even if your IP is so "hidden" and even if you make a DNS override in your host is pretty easy to get the real IP of a website. Meaning that they could easily takedown you by a DDoS to the real IP and since your server doesn't have that protection you will be down. If you are in a VPS or dedicated they will surely know to what site is under attack and then shutdown it for a while, if you are on a shared host you have more luck because they won't know what site under that pile of sites is actually the target because the target is the whole machine. Your hosting company will surely start a useless investigation and most likely they will have to put real DDoS protection on just that machine... I believe that is the best option to get cheap premium class DDoS protection (CF business + your host that doesn't know what is happening)
The real way of get protected is simple: DDoS protected webserver and if you are paranoid, put CloudFlare on it. If you run a DDoS protected server with litespeed you will actually avoid the Layer 7 so you won't need CloudFlare.
BTW, when I mean that is easy to get the real IP of a website I mean it. I won't share that knowledge because it actually affects me D: (and everyone else)