Couldn't follow up with the information you've provided. Usually it's possible to use the name to find out its specs, but the available information from Lenovo is sparse.
http://www3.lenovo.com/us/en/desktops-and-all-in-ones/lenovo/h-series/Lenovo-H50-50/p/993K93H0184#tab-tech_specs
You're not wrong to assume the i5-4690k could work with the same socket, but little nuances may be a factor yet. The linked model has the curious 'Up to Intel® Pentium® G3260 Processor' line. Often I would take such a general notice to limit what CPU can be used with that PC, but this seems oddly limiting for a desktop PC.
I would suggest you download something like CPU-Z, install it and then find your motherboard model under the "Mainboard" tab. This would at least give additional information which could aid you.