If you play ranked at the very start of the new season you WILL be placed lower than you were last season. This is just a fact unless you end up winning games in much much higher elos. This is why.
It is IMPOSSIBLE to place higher than Platinum 1. (This is just a fact)
So all Challenger, Master, and Diamond players are being placed in Platinum.
Which in turn puts Platinum players into gold/silver.
So on and so forth.
This means if you don't want to get completely fucked in provisionals wait for Diamond+ players to get back to Diamond+ spreading the out the variation in rank.
It really isn't riot fucking you over its you playing in a smaller variation of elo that puts you lower. Essentially Plat 1 == Challenger which screws every deviation up.
Be smart and wait.