I think for a forward looking organisation that's looking at or using a blended learning framework a key question needs to be asked about who's driving it? Who is the organisation looking to for guidance and leadership, and who should they involve (or not involve) to make it go smoothly?
Firstly it seems obvious if you're looking at bringing in, upgrading or changing your LMS that the answer lies in the question. It's a learning management system. You'd think it would be fairly obvious that whoever is the driving force behind it has some vested interest in learning (and hopefully has some management responsibility to boot). The issue I sometimes see though is an organisation where the LMS implementation is driven exclusively as any other software development or IT project. The issue here is that even if you consult and bring in your L&D people at some stage, the drive has to come from the people looking to utilise the end result. An LMS is about providing the services for learning, that means your principal aims are all around learning so this is your key driver. It doesn't mean you have to have a project manager who comes from L&D (if you have a PM in L&D it really kind of does), but L&D/HR or your training department need to have the biggest influence in your end result.
But it is an IT system essentially right? Could be (although if you've opted for an externally hosted system that's cloud based with no integration it's no more IT than any other portal or web system) but you have to look at the key aims. Would you install a financial institution without engaging and listening to your financial department (you know you have no choice there as they won't pay for it otherwise!)? For me, seeing IT leading an LMS installation is a sure fire way to get the wrong system installed, or at very least, get the right system with the wrong set up in place.
That brings me swiftly to the next point. If you are in L&D leading an LMS change/integration or installation then you MUST and as early as possible involve IT. This is not at any way in contradiction to the piece above, I'm just saying it's learning so lead it out of learning, but it's an IT system and you need to have them engaged and early. Don't wait until you're about to launch before checking that IT is all good with what you've done. Same could be said of a few other departments too, if you have a marketing and/or communication department you need to engage with them as early as possible to make for the most successful of projects.
So if all that seems pretty obvious there's one last point to consider when choosing who to work with to help install your systems... and it goes right back to my first point, it's all about learning. If you want to buy (!) or install (Open Source) an LMS then look for a partner/distributor that's all about Learning and has its focus firmly in that area rather than an IT or simply an onseller. It makes sense of course, but you want to match the expertise of your team with that of the team you're linking with. No-one will doubt there's a different language when IT people speak to each other, but don't underestimate the language of L&D people too, when you talk about performance, development and competencies surely you need the key contacts in the LMS provider to be thinking along the same lines. It also means that when you get trained on the system it will be geared at getting the most out of the system rather than which buttons do which, big difference eh?
In conclusion, the old adage is true about making sure the dog wags the tail and not the other way round, that's both for your team and the team you're engaging with.