It seems that .arff files can only be produced by Weka data mining software, so only way to create from .csv file would be to import that to Weka and use the data for making .arff files.
Convert Comma Separated Value to Weka attribute-relation data.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert csv to arff on Windows
A machine learning software to solve data mining problems
Convert from csv file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.