This would probably work with just a simple XLR → ¼"TS cable. An impedance transformer would give you higher signal level, but isn't really needed.
Nevertheless, if you can afford it I would recommend you actually use a proper microphone preamp. Standalone preamps are sold mostly for studio applications; typically the main feature is that they use a tube instead of just transistors. Now, you may not need a tube, but it actually does improve the sound of many instruments and if you're going for a bit of a “dirty electric flute” then it is probably right for you as well. A tube-driven signal is a bit compressed and saturated, which will make it come out better in a band mix; unlike guitar-specific overdrives however, a tube preamp can also be made to sound as clean as you want and will not dramatically increase the feedback susceptibility. Most preamps actually have a phase invert switch: this often helps a lot to reduce feedback in live applications but is absent in guitar effects.
The preamp will also offer a better SNR, and it provides phantom power from the power supply so you won't need a battery. (Which means you can use a small in-line adapter like the Audix APS910, instead of the clunky box APS911.)
Two models you could look into are the ART TubeMP and Presonus TubePre.
With both a simple adapter or transformer as well as with a preamp you may run into mains hum issues, because the guitar FX has an unbalanced input. This may be fixable by experimenting with various grounding configurations – unfortunately there's no silver-bullet solution. ...Well, there is actually: using balanced connection, but this is one of the things the guitar world has unfortunately never learned. Depending on what kind of effect you need, you may however be able to get a version intended for vocalists instead, and that would then have balanced XLR connectors already.