Ranked at the beginning of the season?

I ended the last season as gold 4 and went W:4/L:6 in my placement matches and was placed in silver 4. I ended "season 4" at silver 1 but i was gold 4 before season 5 started (so i guess it was preseason). Does anyone know if the placement (regardless of how many wins or losses) is based on what you ended the official season with, or if it depends on what rank you are before the next season starts? Also, does anyone recommend waiting to play ranked until the players are placed in their respective elos? (by "respective elos" i mean outside of placement matches, been playing a while so people that had bad luck in placements or good luck go back down or back up in elo to their "respective" bracket). Thanks for the input.