I second Bodo's answer concerning the fact that "à la carte" is used and should/mostly will be written with an accent.
Note, however, that, at least in Germany, the definition is even a bit "wider": "À la carte" does mean in a general sense that you order the pre-defined dishes from the menu (the list of offered dishes). The contrast to that is not just a fixed, pre-arranged menu of several courses1, "à la carte" can also be used to indicate you are going to order from the menu instead of getting the buffet offer in a restaurant that has a self-service buffet or similar services.
1: And even that one is not as clear-cut: I can imagine three arrangements for getting a fixed multi-course "Menü":
- The restaurant only offers that one (or a few) fixed multi-course "Menüs". Arguably, this is not "à la carte".
- The restaurant offers a set of fixed multi-course "Menüs" beside lots of individual dishes. In this case, the multi-course "Menü" is most probably found in the menu (the list of available dishes), like any other offer by the restaurant. Thus, implying that this should not count as "à la carte" sounds somewhat contradictory.
- You are invited (presumably to some larger celebration), or the restaurant visit is booked and paid for via some external arrangement (tourist group, business meeting, discount voucher, ...) and you get a fixed set of courses without any way to influence these (maybe except for choosing one out of two or three alternatives for a given course). This would be the standard example for "not à la carte".