problem with oe french ligature

Hello,
I tried to use the command\oe for french ligature in the attached LyX file,
but it is not compiled.
Anybody could say what is wrong in this simple file?
THanks a lot for your help and also for the great mailing list so usefull!!
Harold

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Harold Mouras
Doctorant/ATER Université Paris 5
Inserm U483
Boite 23
9, quai Saint Bernard
75005 Paris
Téléphone : +33 1 44 27 26 24
Télécopie : +33 1 44 27 34 38
hmouras@xxxxxxxxxxxxxx
harold.mouras@xxxxxxxxxxxxxx
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example.lyx
Description: Binary data