Does Louisiana have a right to rescission law with regard to apartment leases? If, so do week-ends count?

She doesn't have many legal options. Having signed a lease, she may be held to its terms, including paying rent for the entire term of the lease. The fact that the apartment is located in a bad area is of no concern to the landlord.  It was incumbent upon her to check on all of this first, before signing.  I realize that this seems harsh but it is how the law looks upon such a situation.  Additionally, there is no right to rescission for a lease, so the fact that you never took possession does not matter.

However, the landlord does has a duty to reduce (mitigate) damages by re-renting the apartment and may not hold you liable under the lease once a new tenant starts renting. Yet while the landlord must make a good faith effort to re-rent, that's no guarantee of success. You can help them and yourself by finding someone who will take over from you, either as a sublet or an assignment.  L, however, you are responsible for the rent for the lease term or until the space is rented to someone else.