If I remember corectly, you came out from the Funerary Chamber and out to the corridor.
Now you go right and just before the maze is a door that you can peek inside and see the altar. There is that gold maze map.
Go back to the other end of the corridor, pass the funerary chamber and harp and whatever to the very start when you just came in from the pyramid.
There's a room there similar to this one with a lever - that's the one.
One of this day, I will replay and revise this walkthrough. It's my very first walkthrough.

Thank you MAG. I will see if I can find it and will let you know how I do.

GarfieldOdi

GarfieldOdi,
I'm sure you're on you way with mag's help, but if not. Go back to the two big seated statues. Face them, turn left, click until you see a doorway to your left that looks like the Primitive I. This should be open, turn left to enter the Primitive II. (this is different from Mag's walkthrough and if you can, follow her directions, as it should work better, as you are using her walkthrough).
Charllotte

Thank you MAG and Charllotte. I followed the directions that MAG gave me and it worked just fine. Now I'm in the Lotus Dome Chamber within the maze. I love this game.

GarfieldOdi

Great My favorite.
Charllotte

I finished Riddle of the Sphinx. What a great game. Thanks to everyone who helped me get through the hard parts.

GarfieLdOdi

I love the game. Glad you finished and enjoyed it.
I also revised the walkthrough and refreshed my memory of the game.