The save file can be found here:
C:\Users\<user>\AppData\LocalLow\Rubeki Games\LornsLure\save.dat

Right click and edit with notepad.

Crtl + F and search for GameProgress

Change number from GameProgress:2 to GameProgress:3.

Save the file.

Relaunch the game and start at chapter 4.

If you accidentally went through the hole the second time and are trapped
Open the save file following the instructions above and search for
Caves_lastCheckpointName

Change it to "Caves_lastCheckpointName":"InvisibleCheckpoint (0)" and save.

This will set your spawn point at the elevator.