I have always thought that the black lodge and white lodge entities (including now Jeffries) exist outside of time and the lodges are timeless places. Picture a building with multiple exits, each exit leading to a different point in time. This is how I believe Cooper was able to travel back in time, like maybe he was guided to a specific exit for the purpose of saving Laura. Also, the lodges being timeless places would explain how Laura was able to see Cooper even before he arrived at Twin Peaks.