LCC requires decisions during R&D phase. Just at this moment is when you need to start the LCC analysis. A silly example, you are working on R&D and you have 2 designs for a solution; both requires the same cost for manufacturing but the maintenance is cheaper in one of the cases.
Of course real life is a little bit complex, but this process is necessary to avoid unexpected expenses at a point where you have not an alternative.
The scope of this LCC is all the cost to the organization for the creation of a product/solution: R&D, production, operation, support…
Then, what you have to do is the systematic evaluation of alternatives with the objective of chosing the best way to employ your resources.
You can detect a good/bad business analyst just seeing the way they take care about the future expenses of its analysis.