The Lamp-post: the Way to the World of Men?

Edmund's first visit to Narnia is, as we know, when he becomes entrapped by the promises and delights of the White Witch. Though, by the end of their meeting, Edmund is ready to follow the Witch anywhere, she insists that he go back and bring his brother and sisters. Edmund claims not to know the way back, to which the Witch replies:

"That's easy," answered the Queen. "Do you see that lamp?" She pointed with her wand and Edmund turned and saw the same lamp-post under which Lucy had met the Faun. "Straight on, beyond that, is the way to the World of Men..." 

It is not stated that Edmund ever noticed the lamp-post and he certainly said nothing about it to the White Witch. Neither Lucy nor Tumnus had spoken to the Witch at this point, so how does the Witch know the way to the World of Men? 

How is it so easy? 

Photo by Spencer Bergen on Unsplash