The purpose of initial conversation with people is to get them present. You don't want them thinking about work or babysitters, or if they have enough time at the parking meter. You want them relaxed, comfortable, and most importantly, present. This isn't small talk. You have a very specific purpose and that's to get their brain in the room. Talk with them and help them release any distractions that could interfere with the meeting. Some things that you may want to consider: welcome them, introduce them to any present team members that will be in the meeting, provide drink options, take coats, major/minor tragedies to talk about, how their ride was to the office, how their day is going so far.

You could comment about the weather. You could comment about local sports teams. You could confirm the time that they've allocated for the meeting and respect that. You could convene to the meeting space for all kinds of things that you could talk about or do that will help them become present. Here's a simple action task: make a list of the common topics that you use with current clients to get people present. You might use some of the ones listed a second ago or maybe there're other things that you talk about with your clients. Either way, get a list together so that you don't have to make it up on the spot.