In the present study we attempt to explore the origin of hysteresis in disordered porous media by testing the validity of a recently developed lattice gas model against experimental findings obtained from SAXS studies. Hence, we study the sorption-desorption of CH2Br2 in Vycor at 300 K, by means of Monte Carlo simulations in stochastic reconstructions of Vycor porous glass. By varying the solid-fluid interaction over the fluid-fluid interaction, we are able to match the experimentally measured hysteresis loop. Comparison between the simulation results and experimental measurements of the two-point correlation functions of wet (preadsorbed with CH2Br2) Vycor, obtained from SAXS measurements, reveals that the lattice model is capable of predicting the distinct long-range correlation behavior that occurs in the pore space of the material during desorption. Visual images of the simulated fluid configurations show a clustering of the sorbed phase during desorption which is believed to be responsible for the long-range correlation. Additional simulations in two-dimensions indicate the presence of a complex density field where both pore blocking and cavitation can take place at different regions of the porous matrix.